3 arguments that suggest that the universe is actually quite small

Jonmaas
Predict
Published in
8 min readJul 3, 2020

--

One day, in fact, every human might be able to fit the universe in their pocket

First of all, let’s get this out of the way — at first glance, the universe is impossibly, and inconceivably big.

And it is — take this image:

Hubble Ultra Deep Field image from https://spacetelescope.org/images/heic0406a/
The Hubble Ultra Deep Field

This is the Hubble Ultra Deep Field image, and at first glance it just looks like a bunch of stars.

It’s a lot more than that though — a lot more.

This image holds not stars, but galaxies, galaxies that each contain around 100 billion stars!

And it gets bigger.

The image above holds 10,000 of these galaxies!

And it gets bigger.

The Hubble Ultra Deep Field image represents one thirty-two millionth of the night sky, the equivalent space of a tennis ball 100 meters away.

That is big, inconceivably big.

The size of the universe is inconceivable when considering it in conventional terms.

So let’s think about the universe in unconventional terms, terms that make it quite small.

Argument 1 — Realizing that the universe, as big as it is now, was once the size of a grain of sand

If you dial time back to the beginning, to the universe being about 10^–34 of a second old, we see that the universe went from subatomic size to about the size of a golf ball.

A short time before that, the universe was the size of a grain of sand.

Image from photographer Burst on Stocksnap
There is a lot of sand on her, just look at one grain though

What does that mean?

It does not deny the current size of the universe, but still―our entire universe, with all its energy, its matter and all that space in between―could still fit into a grain of sand.

All of our cities, Jupiter, the Sun, all those galaxies in the Deep Field image―they were once all in something the size of a grain of sand.

So in that sense―though our universe is not currently small, it once was.

And if the universe eventually contracts into a Big Crunch, which some people believe it might, you could describe its future state as small at least, as very, very small.

Argument 2 — Realizing that a human could cross the breadth of the universe in 56 years

Yes, a human could travel the breadth of the universe in 56 years.

Ann Druyan from Wikimedia Commons
Ann Druyan - the writer of Cosmos

Paraphrasing Ann Druyan from Cosmos―

A human could get into a spaceship, and travel at the relatively comfortable acceleration of 1g.

This acceleration would be relatively comfortable for the passenger, because such an acceleration would just feel like normal gravity.

After two years, the ship would be traveling at a velocity very near the speed of light. Then the ship could stop accelerating, and just coast at this speed.

The passenger would then float in zero gravity for 52 years of their life.

After this, they would begin a deceleration process, and decelerate at -1g for two years.

This deceleration would also feel like gravity to the passenger.

And then they would come to a stop 56 years later, and would be across the universe.

Why would they be so far away in just 56 years?

Because they were traveling at a speed near the speed of light, so time would have slowed down for them.

So though only 56 years would have passed for the passenger, billions of years would have passed outside, and the passenger would arrive billions of light years away, on the other side of the universe.

There are, of course, some difficulties to this.

First of all, you need to make a ship that can accelerate at this speed for two years, and be able to survive the top speed.

When you are going near the speed of light, a collision with a penny-sized piece of space debris would rip your ship in half, so there would be a great challenge there.

And even if you could survive the journey, the time difference would all but ensure that earth would be gone by the time you arrive.

The passenger might arrive at their destination and be the last human in the universe.

And of course, the universe would have changed during that time. It might have expanded, or contracted, so the passenger wouldn’t exactly be on the other side of the universe.

They might be in another part, or perhaps beyond it!

But regardless, Ann Druyan noted that it was possible―as big as the universe is, we could traverse a great deal of it in a single lifetime, at least in theory.

Argument 3 — Max Tegmark may eventually put the entire universe in each of our pockets

Max Tegmark is an unconventional thinker when it comes to the universe.

He has noted that we might effectively be alone in the universe, i.e. so far apart from any alien neighbor that we will never be able to communicate with them.

But though some consider Tegmark to be an ET-naysayer, I find him remarkably positive in his conception of the universe.

In his book Our Mathematical Universe: My Quest for the Ultimate Nature of Reality, Tegmark states that most of the universe, if not all, can be defined in mathematical terms:

Even though our two intellectual expeditions set off in opposite directions, toward the large and the small, they ended up in the same place: in the realm of mathematical structures.

When you get really big or really small in this universe, everything can be conceived of as mathematical structures.

That is an interesting way of looking at the universe, and one that gives us a great deal of insight.

Tegmark suggests that though the medium sized objects may be a mystery, the small and large our within our realm of understanding

Let’s take a look at this —

Medium objects

The human mind is quite complex, and we might never fully understand it.

Our own oceans remain largely unexplored, and we might never be able to fully explore them.

The small

But atoms? We might fully understand them one day. It’s just math.

Big and Bigger

And solar systems, galaxies and galaxy clusters not our own?

Again, we’ll understand them―again, it’s just math.

A good example of Tegmark’s mathematical structures cutting through the noise is our search for exoplanets

There are many ways to find planets outside our solar system, and one of them, the transit method, is remarkably straightforward.

Image from https://exoplanets.nasa.gov/alien-worlds/ways-to-find-a-planet/
The transit method of finding Exoplanets

In short:

1) Find a star

2) Measure the change in intensity of its light

3) Its light intensity will change when a planet is rotating in front of it, so after a while, you can determine how many planets it has, what size they are, and the composition of the planet’s atmosphere and its temperature.

And that’s it.

Through this method, we’ve already discovered 3,170 exoplanets.

Just a little bit of math, and we’ve found 3,170 exoplanets.

Now let’s amp our math up a notch, and see what the future might hold.

Spoiler alert: the future might hold the entire universe.

Tegmark and Quantum Computing may put the entire universe in our pocket

Let’s first take the Tegmark assumption that big and small parts of our universe can both be conceived of as mathematical structures.

This is a fair assumption, in my humble opinion.

Let’s also extrapolate our own computing power to its potential, which might be infinite.

A quantum processor, for a quantum computer — from Wikimedia Commons
This is a quantum processor for a quantum computer

Since quantum computing employs an infinite amount of quantum states, our computing power might be infinite―so this is a fair assumption as well, in my humble opinion.

Here’s the insight: Though our travels across the universe may be limited by our size, our mortality and the speed of light―our computing power holds no such limits.

We don’t need to worry about making a ship that can travel far, let alone allowing a human to survive the journey.

We just need to make faster, and faster computers―which given our trajectory, we are going to do.

And then we need to collect more data, and then extrapolate.

The universe in the pocket

Mount Pleasant Radio Telescope — Wikimedia Commons
Mount Pleasant Radio Telescope

Think of it: we collect data with ever more powerful telescopes and satellites, and then process the data with ever more powerful quantum computers.

These quantum computers build an ever more detailed, and ever more accurate map of our universe.

We observe the universe indirectly through data and extrapolation, but our computing power allows that indirect observation to be incredibly accurate.

And then we may one day be able explore the universe in the same way we can explore the world today through Google Maps.

You have a general idea of where you want to explore, you zoom in and then see what’s there.

Or you add a filter, like systems with binary stars, you zoom in and then see what’s there.

Or you find a quadrant at random, zoom in and see what’s there.

And like Google maps, this power will belong to every individual.

Each person might have a quantum computer, or even a quantum thumb drive that contains the universe. And they can keep that quantum device in their pocket.

An exploration of the universe through Tegmark-thinking might be indirect, but it may also be quite possible

The inconvenient truth about our physical place in the universe is that we might be bound to our backwater of the Milky Way by a cavalcade of harsh realities: we are small, we are mortal, and we can’t go fast enough to go anywhere.

But when it comes to our computing potential, there is no such can’t. There may be no limitations, from our size, from our mortality, or from the speed of light.

When it comes to answering a question with our computers, the answer may be yes.

When you consider the universe in Tegmark’s mathematical terms, the chances of a computed yes increase dramatically.

And to backtrack a bit, we shouldn’t say can’t in terms of our potential for actual space travel. Even if we can’t escape our own mortality and the limits of the speed of light, we might find ways to go around both.

But exploring the universe through computers is something that it looks like we can do, and we won’t have to go around any limitations born of our own biology or the laws of physics.

When it comes to our computing potential, the answer is yes, and the universe―as big as it is―is quite small.

Jonathan Maas has a few books on Amazon. He can be found at Goodreads.com/JMaas

--

--

Jonmaas
Predict

I read a lot and occasionally write ;) See more of me at Goodreads.com/JMaas